Continued with assembling the window frames, frustrated by the poor quality of these.  I could have made a better job for sure.  The first needed adjustment to bring the droplight slides into line.  The  second one I worked on turned out to be better dimensionally and need little fettling.  These are a long job requiring many holes to be drilled and trial assembly.  I completed two by the end of Friday and started on a third, which was largely complete by the end of the week.

Droplight frames awaiting building up and fitting.